1. Field of the Invention
The present invention relates generally to location information systems, and more specifically to a gateway which interfaces between client terminals and a location information system.
2. Description of the Related Art
According to the state-of-the-art location information system, a client terminal sends a location request message to a gateway of a wireless access network when the client desires the location information of a target mobile user equipment (UE) terminal. In response to the client request message, the gateway stores the address of the client terminal in a management table and assigns a serial number and requests the access network to establish a connection to a location information server. The gateway sends a request message to the location information server, containing the address of the target UE terminal and the serial number. Using a global or local positioning system, the location information server obtains the location information of the target UE and transmits this information in a location response message to the gateway, containing the serial number. In response, the gateway searches the management table for a client terminal assigned the same serial number as that of the received response message and transmits the received location information to the client terminal.
Therefore, for every client's location request, the state-of-the-art gateway sends a request to the location information server, regardless of whether there is another client's request requesting the location information of the same mobile terminal. Since the acquisition of location information is a costly process, there exists a need to reduce the acquisition cost when the location information of a mobile terminal is requested simultaneously from a number of client terminals.